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C++: Deprecate DefaultTaintTracking and TaintTrackingImpl

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Jeroen Ketema
2022-11-25 14:23:16 +01:00
parent 2c500142c7
commit b5147bbfb0
22 changed files with 701 additions and 655 deletions
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cpp/ql/lib/semmle/code/cpp/ir/dataflow/DefaultTaintTracking.qll
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@@ -1,642 +1,21 @@
/**
* DEPRECATED: Use `semmle.code.cpp.ir.dataflow.TaintTracking` as a replacement.
*
* An IR taint tracking library that uses an IR DataFlow configuration to track
* taint from user inputs as defined by `semmle.code.cpp.security.Security`.
*/
import cpp
import semmle.code.cpp.security.Security
private import semmle.code.cpp.ir.dataflow.DataFlow
private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
private import semmle.code.cpp.ir.dataflow.DataFlow3
private import semmle.code.cpp.ir.IR
private import semmle.code.cpp.ir.dataflow.ResolveCall
private import semmle.code.cpp.controlflow.IRGuards
private import semmle.code.cpp.models.interfaces.Taint
private import semmle.code.cpp.models.interfaces.DataFlow
private import semmle.code.cpp.ir.dataflow.TaintTracking
private import semmle.code.cpp.ir.dataflow.TaintTracking2
private import semmle.code.cpp.ir.dataflow.TaintTracking3
private import semmle.code.cpp.ir.dataflow.internal.ModelUtil
private import semmle.code.cpp.ir.dataflow.internal.DefaultTaintTrackingImpl as DefaultTaintTrackingImpl
/**
* A predictable instruction is one where an external user can predict
* the value. For example, a literal in the source code is considered
* predictable.
*/
private predicate predictableInstruction(Instruction instr) {
instr instanceof ConstantInstruction
or
instr instanceof StringConstantInstruction
or
// This could be a conversion on a string literal
predictableInstruction(instr.(UnaryInstruction).getUnary())
}
deprecated predicate predictableOnlyFlow = DefaultTaintTrackingImpl::predictableOnlyFlow/1;
/**
* Functions that we should only allow taint to flow through (to the return
* value) if all but the source argument are 'predictable'. This is done to
* emulate the old security library's implementation rather than due to any
* strong belief that this is the right approach.
*
* Note that the list itself is not very principled; it consists of all the
* functions listed in the old security library's [default] `isPureFunction`
* that have more than one argument, but are not in the old taint tracking
* library's `returnArgument` predicate.
*/
predicate predictableOnlyFlow(string name) {
name =
[
"strcasestr", "strchnul", "strchr", "strchrnul", "strcmp", "strcspn", "strncmp", "strndup",
"strnlen", "strrchr", "strspn", "strstr", "strtod", "strtof", "strtol", "strtoll", "strtoq",
"strtoul"
]
}
deprecated predicate tainted = DefaultTaintTrackingImpl::tainted/2;
private DataFlow::Node getNodeForSource(Expr source) {
isUserInput(source, _) and
result = getNodeForExpr(source)
}
deprecated predicate taintedIncludingGlobalVars =
DefaultTaintTrackingImpl::taintedIncludingGlobalVars/3;
private DataFlow::Node getNodeForExpr(Expr node) {
result = DataFlow::exprNode(node)
or
// Some of the sources in `isUserInput` are intended to match the value of
// an expression, while others (those modeled below) are intended to match
// the taint that propagates out of an argument, like the `char *` argument
// to `gets`. It's impossible here to tell which is which, but the "access
// to argv" source is definitely not intended to match an output argument,
// and it causes false positives if we let it.
//
// This case goes together with the similar (but not identical) rule in
// `nodeIsBarrierIn`.
result = DataFlow::definitionByReferenceNodeFromArgument(node) and
not argv(node.(VariableAccess).getTarget())
}
deprecated predicate globalVarFromId = DefaultTaintTrackingImpl::globalVarFromId/1;
private class DefaultTaintTrackingCfg extends TaintTracking::Configuration {
DefaultTaintTrackingCfg() { this = "DefaultTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) { source = getNodeForSource(_) }
override predicate isSink(DataFlow::Node sink) { exists(adjustedSink(sink)) }
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private class ToGlobalVarTaintTrackingCfg extends TaintTracking::Configuration {
ToGlobalVarTaintTrackingCfg() { this = "GlobalVarTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) { source = getNodeForSource(_) }
override predicate isSink(DataFlow::Node sink) {
sink.asVariable() instanceof GlobalOrNamespaceVariable
}
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
writesVariable(n1.asInstruction(), n2.asVariable().(GlobalOrNamespaceVariable))
or
readsVariable(n2.asInstruction(), n1.asVariable().(GlobalOrNamespaceVariable))
}
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private class FromGlobalVarTaintTrackingCfg extends TaintTracking2::Configuration {
FromGlobalVarTaintTrackingCfg() { this = "FromGlobalVarTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) {
// This set of sources should be reasonably small, which is good for
// performance since the set of sinks is very large.
exists(ToGlobalVarTaintTrackingCfg otherCfg | otherCfg.hasFlowTo(source))
}
override predicate isSink(DataFlow::Node sink) { exists(adjustedSink(sink)) }
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
// Additional step for flow out of variables. There is no flow _into_
// variables in this configuration, so this step only serves to take flow
// out of a variable that's a source.
readsVariable(n2.asInstruction(), n1.asVariable())
}
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private predicate readsVariable(LoadInstruction load, Variable var) {
load.getSourceAddress().(VariableAddressInstruction).getAstVariable() = var
}
private predicate writesVariable(StoreInstruction store, Variable var) {
store.getDestinationAddress().(VariableAddressInstruction).getAstVariable() = var
}
/**
* A variable that has any kind of upper-bound check anywhere in the program. This is
* biased towards being inclusive because there are a lot of valid ways of doing an
* upper bounds checks if we don't consider where it occurs, for example:
* ```
* if (x < 10) { sink(x); }
*
* if (10 > y) { sink(y); }
*
* if (z > 10) { z = 10; }
* sink(z);
* ```
*/
// TODO: This coarse overapproximation, ported from the old taint tracking
// library, could be replaced with an actual semantic check that a particular
// variable _access_ is guarded by an upper-bound check. We probably don't want
// to do this right away since it could expose a lot of FPs that were
// previously suppressed by this predicate by coincidence.
private predicate hasUpperBoundsCheck(Variable var) {
exists(RelationalOperation oper, VariableAccess access |
oper.getAnOperand() = access and
access.getTarget() = var and
// Comparing to 0 is not an upper bound check
not oper.getAnOperand().getValue() = "0"
)
}
private predicate nodeIsBarrierEqualityCandidate(
DataFlow::Node node, Operand access, Variable checkedVar
) {
readsVariable(node.asInstruction(), checkedVar) and
any(IRGuardCondition guard).ensuresEq(access, _, _, node.asInstruction().getBlock(), true)
}
cached
private module Cached {
cached
predicate nodeIsBarrier(DataFlow::Node node) {
exists(Variable checkedVar |
readsVariable(node.asInstruction(), checkedVar) and
hasUpperBoundsCheck(checkedVar)
)
or
exists(Variable checkedVar, Operand access |
/*
* This node is guarded by a condition that forces the accessed variable
* to equal something else. For example:
* ```
* x = taintsource()
* if (x == 10) {
* taintsink(x); // not considered tainted
* }
* ```
*/
nodeIsBarrierEqualityCandidate(node, access, checkedVar) and
readsVariable(access.getDef(), checkedVar)
)
}
cached
predicate nodeIsBarrierIn(DataFlow::Node node) {
// don't use dataflow into taint sources, as this leads to duplicate results.
exists(Expr source | isUserInput(source, _) |
node = DataFlow::exprNode(source)
or
// This case goes together with the similar (but not identical) rule in
// `getNodeForSource`.
node = DataFlow::definitionByReferenceNodeFromArgument(source)
)
or
// don't use dataflow into binary instructions if both operands are unpredictable
exists(BinaryInstruction iTo |
iTo = node.asInstruction() and
not predictableInstruction(iTo.getLeft()) and
not predictableInstruction(iTo.getRight()) and
// propagate taint from either the pointer or the offset, regardless of predictability
not iTo instanceof PointerArithmeticInstruction
)
or
// don't use dataflow through calls to pure functions if two or more operands
// are unpredictable
exists(Instruction iFrom1, Instruction iFrom2, CallInstruction iTo |
iTo = node.asInstruction() and
isPureFunction(iTo.getStaticCallTarget().getName()) and
iFrom1 = iTo.getAnArgument() and
iFrom2 = iTo.getAnArgument() and
not predictableInstruction(iFrom1) and
not predictableInstruction(iFrom2) and
iFrom1 != iFrom2
)
}
cached
Element adjustedSink(DataFlow::Node sink) {
// TODO: is it more appropriate to use asConvertedExpr here and avoid
// `getConversion*`? Or will that cause us to miss some cases where there's
// flow to a conversion (like a `ReferenceDereferenceExpr`) and we want to
// pretend there was flow to the converted `Expr` for the sake of
// compatibility.
sink.asExpr().getConversion*() = result
or
// For compatibility, send flow from arguments to parameters, even for
// functions with no body.
exists(FunctionCall call, int i |
sink.asExpr() = call.getArgument(pragma[only_bind_into](i)) and
result = resolveCall(call).getParameter(pragma[only_bind_into](i))
)
or
// For compatibility, send flow into a `Variable` if there is flow to any
// Load or Store of that variable.
exists(CopyInstruction copy |
copy.getSourceValue() = sink.asInstruction() and
(
readsVariable(copy, result) or
writesVariable(copy, result)
) and
not hasUpperBoundsCheck(result)
)
or
// For compatibility, send flow into a `NotExpr` even if it's part of a
// short-circuiting condition and thus might get skipped.
result.(NotExpr).getOperand() = sink.asExpr()
or
// Taint postfix and prefix crement operations when their operand is tainted.
result.(CrementOperation).getAnOperand() = sink.asExpr()
or
// Taint `e1 += e2`, `e &= e2` and friends when `e1` or `e2` is tainted.
result.(AssignOperation).getAnOperand() = sink.asExpr()
or
result =
sink.asOperand()
.(SideEffectOperand)
.getUse()
.(ReadSideEffectInstruction)
.getArgumentDef()
.getUnconvertedResultExpression()
}
/**
* Step to return value of a modeled function when an input taints the
* dereference of the return value.
*/
cached
predicate additionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
exists(CallInstruction call, Function func, FunctionInput modelIn, FunctionOutput modelOut |
n1.asOperand() = callInput(call, modelIn) and
(
func.(TaintFunction).hasTaintFlow(modelIn, modelOut)
or
func.(DataFlowFunction).hasDataFlow(modelIn, modelOut)
) and
call.getStaticCallTarget() = func and
modelOut.isReturnValueDeref() and
call = n2.asInstruction()
)
}
}
private import Cached
/**
* Holds if `tainted` may contain taint from `source`.
*
* A tainted expression is either directly user input, or is
* computed from user input in a way that users can probably
* control the exact output of the computation.
*
* This doesn't include data flow through global variables.
* If you need that you must call `taintedIncludingGlobalVars`.
*/
cached
predicate tainted(Expr source, Element tainted) {
exists(DefaultTaintTrackingCfg cfg, DataFlow::Node sink |
cfg.hasFlow(getNodeForSource(source), sink) and
tainted = adjustedSink(sink)
)
}
/**
* Holds if `tainted` may contain taint from `source`, where the taint passed
* through a global variable named `globalVar`.
*
* A tainted expression is either directly user input, or is
* computed from user input in a way that users can probably
* control the exact output of the computation.
*
* This version gives the same results as tainted but also includes
* data flow through global variables.
*
* The parameter `globalVar` is the qualified name of the last global variable
* used to move the value from source to tainted. If the taint did not pass
* through a global variable, then `globalVar = ""`.
*/
cached
predicate taintedIncludingGlobalVars(Expr source, Element tainted, string globalVar) {
tainted(source, tainted) and
globalVar = ""
or
exists(
ToGlobalVarTaintTrackingCfg toCfg, FromGlobalVarTaintTrackingCfg fromCfg,
DataFlow::VariableNode variableNode, GlobalOrNamespaceVariable global, DataFlow::Node sink
|
global = variableNode.getVariable() and
toCfg.hasFlow(getNodeForSource(source), variableNode) and
fromCfg.hasFlow(variableNode, sink) and
tainted = adjustedSink(sink) and
global = globalVarFromId(globalVar)
)
}
/**
* Gets the global variable whose qualified name is `id`. Use this predicate
* together with `taintedIncludingGlobalVars`. Example:
*
* ```
* exists(string varName |
* taintedIncludingGlobalVars(source, tainted, varName) and
* var = globalVarFromId(varName)
* )
* ```
*/
GlobalOrNamespaceVariable globalVarFromId(string id) { id = result.getQualifiedName() }
/**
* Provides definitions for augmenting source/sink pairs with data-flow paths
* between them. From a `@kind path-problem` query, import this module in the
* global scope, extend `TaintTrackingConfiguration`, and use `taintedWithPath`
* in place of `tainted`.
*
* Importing this module will also import the query predicates that contain the
* taint paths.
*/
module TaintedWithPath {
private newtype TSingleton = MkSingleton()
/**
* A taint-tracking configuration that matches sources and sinks in the same
* way as the `tainted` predicate.
*
* Override `isSink` and `taintThroughGlobals` as needed, but do not provide
* a characteristic predicate.
*/
class TaintTrackingConfiguration extends TSingleton {
/** Override this to specify which elements are sources in this configuration. */
predicate isSource(Expr source) { exists(getNodeForSource(source)) }
/** Override this to specify which elements are sinks in this configuration. */
abstract predicate isSink(Element e);
/** Override this to specify which expressions are barriers in this configuration. */
predicate isBarrier(Expr e) { nodeIsBarrier(getNodeForExpr(e)) }
/**
* Override this predicate to `any()` to allow taint to flow through global
* variables.
*/
predicate taintThroughGlobals() { none() }
/** Gets a textual representation of this element. */
string toString() { result = "TaintTrackingConfiguration" }
}
private class AdjustedConfiguration extends TaintTracking3::Configuration {
AdjustedConfiguration() { this = "AdjustedConfiguration" }
override predicate isSource(DataFlow::Node source) {
exists(TaintTrackingConfiguration cfg, Expr e |
cfg.isSource(e) and source = getNodeForExpr(e)
)
}
override predicate isSink(DataFlow::Node sink) {
exists(TaintTrackingConfiguration cfg | cfg.isSink(adjustedSink(sink)))
}
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
// Steps into and out of global variables
exists(TaintTrackingConfiguration cfg | cfg.taintThroughGlobals() |
writesVariable(n1.asInstruction(), n2.asVariable().(GlobalOrNamespaceVariable))
or
readsVariable(n2.asInstruction(), n1.asVariable().(GlobalOrNamespaceVariable))
)
or
additionalTaintStep(n1, n2)
}
override predicate isSanitizer(DataFlow::Node node) {
exists(TaintTrackingConfiguration cfg, Expr e | cfg.isBarrier(e) and node = getNodeForExpr(e))
}
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
/*
* A sink `Element` may map to multiple `DataFlowX::PathNode`s via (the
* inverse of) `adjustedSink`. For example, an `Expr` maps to all its
* conversions, and a `Variable` maps to all loads and stores from it. Because
* the path node is part of the tuple that constitutes the alert, this leads
* to duplicate alerts.
*
* To avoid showing duplicates, we edit the graph to replace the final node
* coming from the data-flow library with a node that matches exactly the
* `Element` sink that's requested.
*
* The same is done for sources.
*/
private newtype TPathNode =
TWrapPathNode(DataFlow3::PathNode n) or
// There's a single newtype constructor for both sources and sinks since
// that makes it easiest to deal with the case where source = sink.
TEndpointPathNode(Element e) {
exists(AdjustedConfiguration cfg, DataFlow3::Node sourceNode, DataFlow3::Node sinkNode |
cfg.hasFlow(sourceNode, sinkNode)
|
sourceNode = getNodeForExpr(e) and
exists(TaintTrackingConfiguration ttCfg | ttCfg.isSource(e))
or
e = adjustedSink(sinkNode) and
exists(TaintTrackingConfiguration ttCfg | ttCfg.isSink(e))
)
}
/** An opaque type used for the nodes of a data-flow path. */
class PathNode extends TPathNode {
/** Gets a textual representation of this element. */
string toString() { none() }
/**
* Holds if this element is at the specified location.
* The location spans column `startcolumn` of line `startline` to
* column `endcolumn` of line `endline` in file `filepath`.
* For more information, see
* [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
*/
predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
none()
}
}
/**
* INTERNAL: Do not use.
*/
module Private {
/** Gets a predecessor `PathNode` of `pathNode`, if any. */
PathNode getAPredecessor(PathNode pathNode) { edges(result, pathNode) }
/** Gets the element that `pathNode` wraps, if any. */
Element getElementFromPathNode(PathNode pathNode) {
exists(DataFlow::Node node | node = pathNode.(WrapPathNode).inner().getNode() |
result = node.asInstruction().getAst()
or
result = node.asOperand().getDef().getAst()
)
or
result = pathNode.(EndpointPathNode).inner()
}
}
private class WrapPathNode extends PathNode, TWrapPathNode {
DataFlow3::PathNode inner() { this = TWrapPathNode(result) }
override string toString() { result = this.inner().toString() }
override predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
this.inner().hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
}
}
private class EndpointPathNode extends PathNode, TEndpointPathNode {
Expr inner() { this = TEndpointPathNode(result) }
override string toString() { result = this.inner().toString() }
override predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
this.inner()
.getLocation()
.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
}
}
/** A PathNode whose `Element` is a source. It may also be a sink. */
private class InitialPathNode extends EndpointPathNode {
InitialPathNode() { exists(TaintTrackingConfiguration cfg | cfg.isSource(this.inner())) }
}
/** A PathNode whose `Element` is a sink. It may also be a source. */
private class FinalPathNode extends EndpointPathNode {
FinalPathNode() { exists(TaintTrackingConfiguration cfg | cfg.isSink(this.inner())) }
}
/** Holds if `(a,b)` is an edge in the graph of data flow path explanations. */
query predicate edges(PathNode a, PathNode b) {
DataFlow3::PathGraph::edges(a.(WrapPathNode).inner(), b.(WrapPathNode).inner())
or
// To avoid showing trivial-looking steps, we _replace_ the last node instead
// of adding an edge out of it.
exists(WrapPathNode sinkNode |
DataFlow3::PathGraph::edges(a.(WrapPathNode).inner(), sinkNode.inner()) and
b.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
or
// Same for the first node
exists(WrapPathNode sourceNode |
DataFlow3::PathGraph::edges(sourceNode.inner(), b.(WrapPathNode).inner()) and
sourceNode.inner().getNode() = getNodeForExpr(a.(InitialPathNode).inner())
)
or
// Finally, handle the case where the path goes directly from a source to a
// sink, meaning that they both need to be translated.
exists(WrapPathNode sinkNode, WrapPathNode sourceNode |
DataFlow3::PathGraph::edges(sourceNode.inner(), sinkNode.inner()) and
sourceNode.inner().getNode() = getNodeForExpr(a.(InitialPathNode).inner()) and
b.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
}
/**
* Holds if there is flow from `arg` to `out` across a call that can by summarized by the flow
* from `par` to `ret` within it, in the graph of data flow path explanations.
*/
query predicate subpaths(PathNode arg, PathNode par, PathNode ret, PathNode out) {
DataFlow3::PathGraph::subpaths(arg.(WrapPathNode).inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), out.(WrapPathNode).inner())
or
// To avoid showing trivial-looking steps, we _replace_ the last node instead
// of adding an edge out of it.
exists(WrapPathNode sinkNode |
DataFlow3::PathGraph::subpaths(arg.(WrapPathNode).inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), sinkNode.inner()) and
out.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
or
// Same for the first node
exists(WrapPathNode sourceNode |
DataFlow3::PathGraph::subpaths(sourceNode.inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), out.(WrapPathNode).inner()) and
sourceNode.inner().getNode() = getNodeForExpr(arg.(InitialPathNode).inner())
)
or
// Finally, handle the case where the path goes directly from a source to a
// sink, meaning that they both need to be translated.
exists(WrapPathNode sinkNode, WrapPathNode sourceNode |
DataFlow3::PathGraph::subpaths(sourceNode.inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), sinkNode.inner()) and
sourceNode.inner().getNode() = getNodeForExpr(arg.(InitialPathNode).inner()) and
out.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
}
/** Holds if `n` is a node in the graph of data flow path explanations. */
query predicate nodes(PathNode n, string key, string val) {
key = "semmle.label" and val = n.toString()
}
/**
* Holds if `tainted` may contain taint from `source`, where `sourceNode` and
* `sinkNode` are the corresponding `PathNode`s that can be used in a query
* to provide path explanations. Extend `TaintTrackingConfiguration` to use
* this predicate.
*
* A tainted expression is either directly user input, or is computed from
* user input in a way that users can probably control the exact output of
* the computation.
*/
predicate taintedWithPath(Expr source, Element tainted, PathNode sourceNode, PathNode sinkNode) {
exists(AdjustedConfiguration cfg, DataFlow3::Node flowSource, DataFlow3::Node flowSink |
source = sourceNode.(InitialPathNode).inner() and
flowSource = getNodeForExpr(source) and
cfg.hasFlow(flowSource, flowSink) and
tainted = adjustedSink(flowSink) and
tainted = sinkNode.(FinalPathNode).inner()
)
}
private predicate isGlobalVariablePathNode(WrapPathNode n) {
n.inner().getNode().asVariable() instanceof GlobalOrNamespaceVariable
}
private predicate edgesWithoutGlobals(PathNode a, PathNode b) {
edges(a, b) and
not isGlobalVariablePathNode(a) and
not isGlobalVariablePathNode(b)
}
/**
* Holds if `tainted` can be reached from a taint source without passing
* through a global variable.
*/
predicate taintedWithoutGlobals(Element tainted) {
exists(AdjustedConfiguration cfg, PathNode sourceNode, FinalPathNode sinkNode |
cfg.isSource(sourceNode.(WrapPathNode).inner().getNode()) and
edgesWithoutGlobals+(sourceNode, sinkNode) and
tainted = sinkNode.inner()
)
}
}
deprecated module TaintedWithPath = DefaultTaintTrackingImpl::TaintedWithPath;

644
cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DefaultTaintTrackingImpl.qll Normal file
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/**
* INTERNAL: Do not use.
*
* An IR taint tracking library that uses an IR DataFlow configuration to track
* taint from user inputs as defined by `semmle.code.cpp.security.Security`.
*/
import cpp
import semmle.code.cpp.security.Security
private import semmle.code.cpp.ir.dataflow.DataFlow
private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
private import semmle.code.cpp.ir.dataflow.DataFlow3
private import semmle.code.cpp.ir.IR
private import semmle.code.cpp.ir.dataflow.ResolveCall
private import semmle.code.cpp.controlflow.IRGuards
private import semmle.code.cpp.models.interfaces.Taint
private import semmle.code.cpp.models.interfaces.DataFlow
private import semmle.code.cpp.ir.dataflow.TaintTracking
private import semmle.code.cpp.ir.dataflow.TaintTracking2
private import semmle.code.cpp.ir.dataflow.TaintTracking3
private import semmle.code.cpp.ir.dataflow.internal.ModelUtil
/**
* A predictable instruction is one where an external user can predict
* the value. For example, a literal in the source code is considered
* predictable.
*/
private predicate predictableInstruction(Instruction instr) {
instr instanceof ConstantInstruction
or
instr instanceof StringConstantInstruction
or
// This could be a conversion on a string literal
predictableInstruction(instr.(UnaryInstruction).getUnary())
}
/**
* Functions that we should only allow taint to flow through (to the return
* value) if all but the source argument are 'predictable'. This is done to
* emulate the old security library's implementation rather than due to any
* strong belief that this is the right approach.
*
* Note that the list itself is not very principled; it consists of all the
* functions listed in the old security library's [default] `isPureFunction`
* that have more than one argument, but are not in the old taint tracking
* library's `returnArgument` predicate.
*/
predicate predictableOnlyFlow(string name) {
name =
[
"strcasestr", "strchnul", "strchr", "strchrnul", "strcmp", "strcspn", "strncmp", "strndup",
"strnlen", "strrchr", "strspn", "strstr", "strtod", "strtof", "strtol", "strtoll", "strtoq",
"strtoul"
]
}
private DataFlow::Node getNodeForSource(Expr source) {
isUserInput(source, _) and
result = getNodeForExpr(source)
}
private DataFlow::Node getNodeForExpr(Expr node) {
result = DataFlow::exprNode(node)
or
// Some of the sources in `isUserInput` are intended to match the value of
// an expression, while others (those modeled below) are intended to match
// the taint that propagates out of an argument, like the `char *` argument
// to `gets`. It's impossible here to tell which is which, but the "access
// to argv" source is definitely not intended to match an output argument,
// and it causes false positives if we let it.
//
// This case goes together with the similar (but not identical) rule in
// `nodeIsBarrierIn`.
result = DataFlow::definitionByReferenceNodeFromArgument(node) and
not argv(node.(VariableAccess).getTarget())
}
private class DefaultTaintTrackingCfg extends TaintTracking::Configuration {
DefaultTaintTrackingCfg() { this = "DefaultTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) { source = getNodeForSource(_) }
override predicate isSink(DataFlow::Node sink) { exists(adjustedSink(sink)) }
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private class ToGlobalVarTaintTrackingCfg extends TaintTracking::Configuration {
ToGlobalVarTaintTrackingCfg() { this = "GlobalVarTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) { source = getNodeForSource(_) }
override predicate isSink(DataFlow::Node sink) {
sink.asVariable() instanceof GlobalOrNamespaceVariable
}
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
writesVariable(n1.asInstruction(), n2.asVariable().(GlobalOrNamespaceVariable))
or
readsVariable(n2.asInstruction(), n1.asVariable().(GlobalOrNamespaceVariable))
}
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private class FromGlobalVarTaintTrackingCfg extends TaintTracking2::Configuration {
FromGlobalVarTaintTrackingCfg() { this = "FromGlobalVarTaintTrackingCfg" }
override predicate isSource(DataFlow::Node source) {
// This set of sources should be reasonably small, which is good for
// performance since the set of sinks is very large.
exists(ToGlobalVarTaintTrackingCfg otherCfg | otherCfg.hasFlowTo(source))
}
override predicate isSink(DataFlow::Node sink) { exists(adjustedSink(sink)) }
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
// Additional step for flow out of variables. There is no flow _into_
// variables in this configuration, so this step only serves to take flow
// out of a variable that's a source.
readsVariable(n2.asInstruction(), n1.asVariable())
}
override predicate isSanitizer(DataFlow::Node node) { nodeIsBarrier(node) }
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
private predicate readsVariable(LoadInstruction load, Variable var) {
load.getSourceAddress().(VariableAddressInstruction).getAstVariable() = var
}
private predicate writesVariable(StoreInstruction store, Variable var) {
store.getDestinationAddress().(VariableAddressInstruction).getAstVariable() = var
}
/**
* A variable that has any kind of upper-bound check anywhere in the program. This is
* biased towards being inclusive because there are a lot of valid ways of doing an
* upper bounds checks if we don't consider where it occurs, for example:
* ```
* if (x < 10) { sink(x); }
*
* if (10 > y) { sink(y); }
*
* if (z > 10) { z = 10; }
* sink(z);
* ```
*/
// TODO: This coarse overapproximation, ported from the old taint tracking
// library, could be replaced with an actual semantic check that a particular
// variable _access_ is guarded by an upper-bound check. We probably don't want
// to do this right away since it could expose a lot of FPs that were
// previously suppressed by this predicate by coincidence.
private predicate hasUpperBoundsCheck(Variable var) {
exists(RelationalOperation oper, VariableAccess access |
oper.getAnOperand() = access and
access.getTarget() = var and
// Comparing to 0 is not an upper bound check
not oper.getAnOperand().getValue() = "0"
)
}
private predicate nodeIsBarrierEqualityCandidate(
DataFlow::Node node, Operand access, Variable checkedVar
) {
readsVariable(node.asInstruction(), checkedVar) and
any(IRGuardCondition guard).ensuresEq(access, _, _, node.asInstruction().getBlock(), true)
}
cached
private module Cached {
cached
predicate nodeIsBarrier(DataFlow::Node node) {
exists(Variable checkedVar |
readsVariable(node.asInstruction(), checkedVar) and
hasUpperBoundsCheck(checkedVar)
)
or
exists(Variable checkedVar, Operand access |
/*
* This node is guarded by a condition that forces the accessed variable
* to equal something else. For example:
* ```
* x = taintsource()
* if (x == 10) {
* taintsink(x); // not considered tainted
* }
* ```
*/
nodeIsBarrierEqualityCandidate(node, access, checkedVar) and
readsVariable(access.getDef(), checkedVar)
)
}
cached
predicate nodeIsBarrierIn(DataFlow::Node node) {
// don't use dataflow into taint sources, as this leads to duplicate results.
exists(Expr source | isUserInput(source, _) |
node = DataFlow::exprNode(source)
or
// This case goes together with the similar (but not identical) rule in
// `getNodeForSource`.
node = DataFlow::definitionByReferenceNodeFromArgument(source)
)
or
// don't use dataflow into binary instructions if both operands are unpredictable
exists(BinaryInstruction iTo |
iTo = node.asInstruction() and
not predictableInstruction(iTo.getLeft()) and
not predictableInstruction(iTo.getRight()) and
// propagate taint from either the pointer or the offset, regardless of predictability
not iTo instanceof PointerArithmeticInstruction
)
or
// don't use dataflow through calls to pure functions if two or more operands
// are unpredictable
exists(Instruction iFrom1, Instruction iFrom2, CallInstruction iTo |
iTo = node.asInstruction() and
isPureFunction(iTo.getStaticCallTarget().getName()) and
iFrom1 = iTo.getAnArgument() and
iFrom2 = iTo.getAnArgument() and
not predictableInstruction(iFrom1) and
not predictableInstruction(iFrom2) and
iFrom1 != iFrom2
)
}
cached
Element adjustedSink(DataFlow::Node sink) {
// TODO: is it more appropriate to use asConvertedExpr here and avoid
// `getConversion*`? Or will that cause us to miss some cases where there's
// flow to a conversion (like a `ReferenceDereferenceExpr`) and we want to
// pretend there was flow to the converted `Expr` for the sake of
// compatibility.
sink.asExpr().getConversion*() = result
or
// For compatibility, send flow from arguments to parameters, even for
// functions with no body.
exists(FunctionCall call, int i |
sink.asExpr() = call.getArgument(pragma[only_bind_into](i)) and
result = resolveCall(call).getParameter(pragma[only_bind_into](i))
)
or
// For compatibility, send flow into a `Variable` if there is flow to any
// Load or Store of that variable.
exists(CopyInstruction copy |
copy.getSourceValue() = sink.asInstruction() and
(
readsVariable(copy, result) or
writesVariable(copy, result)
) and
not hasUpperBoundsCheck(result)
)
or
// For compatibility, send flow into a `NotExpr` even if it's part of a
// short-circuiting condition and thus might get skipped.
result.(NotExpr).getOperand() = sink.asExpr()
or
// Taint postfix and prefix crement operations when their operand is tainted.
result.(CrementOperation).getAnOperand() = sink.asExpr()
or
// Taint `e1 += e2`, `e &= e2` and friends when `e1` or `e2` is tainted.
result.(AssignOperation).getAnOperand() = sink.asExpr()
or
result =
sink.asOperand()
.(SideEffectOperand)
.getUse()
.(ReadSideEffectInstruction)
.getArgumentDef()
.getUnconvertedResultExpression()
}
/**
* Step to return value of a modeled function when an input taints the
* dereference of the return value.
*/
cached
predicate additionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
exists(CallInstruction call, Function func, FunctionInput modelIn, FunctionOutput modelOut |
n1.asOperand() = callInput(call, modelIn) and
(
func.(TaintFunction).hasTaintFlow(modelIn, modelOut)
or
func.(DataFlowFunction).hasDataFlow(modelIn, modelOut)
) and
call.getStaticCallTarget() = func and
modelOut.isReturnValueDeref() and
call = n2.asInstruction()
)
}
}
private import Cached
/**
* Holds if `tainted` may contain taint from `source`.
*
* A tainted expression is either directly user input, or is
* computed from user input in a way that users can probably
* control the exact output of the computation.
*
* This doesn't include data flow through global variables.
* If you need that you must call `taintedIncludingGlobalVars`.
*/
cached
predicate tainted(Expr source, Element tainted) {
exists(DefaultTaintTrackingCfg cfg, DataFlow::Node sink |
cfg.hasFlow(getNodeForSource(source), sink) and
tainted = adjustedSink(sink)
)
}
/**
* Holds if `tainted` may contain taint from `source`, where the taint passed
* through a global variable named `globalVar`.
*
* A tainted expression is either directly user input, or is
* computed from user input in a way that users can probably
* control the exact output of the computation.
*
* This version gives the same results as tainted but also includes
* data flow through global variables.
*
* The parameter `globalVar` is the qualified name of the last global variable
* used to move the value from source to tainted. If the taint did not pass
* through a global variable, then `globalVar = ""`.
*/
cached
predicate taintedIncludingGlobalVars(Expr source, Element tainted, string globalVar) {
tainted(source, tainted) and
globalVar = ""
or
exists(
ToGlobalVarTaintTrackingCfg toCfg, FromGlobalVarTaintTrackingCfg fromCfg,
DataFlow::VariableNode variableNode, GlobalOrNamespaceVariable global, DataFlow::Node sink
|
global = variableNode.getVariable() and
toCfg.hasFlow(getNodeForSource(source), variableNode) and
fromCfg.hasFlow(variableNode, sink) and
tainted = adjustedSink(sink) and
global = globalVarFromId(globalVar)
)
}
/**
* Gets the global variable whose qualified name is `id`. Use this predicate
* together with `taintedIncludingGlobalVars`. Example:
*
* ```
* exists(string varName |
* taintedIncludingGlobalVars(source, tainted, varName) and
* var = globalVarFromId(varName)
* )
* ```
*/
GlobalOrNamespaceVariable globalVarFromId(string id) { id = result.getQualifiedName() }
/**
* Provides definitions for augmenting source/sink pairs with data-flow paths
* between them. From a `@kind path-problem` query, import this module in the
* global scope, extend `TaintTrackingConfiguration`, and use `taintedWithPath`
* in place of `tainted`.
*
* Importing this module will also import the query predicates that contain the
* taint paths.
*/
module TaintedWithPath {
private newtype TSingleton = MkSingleton()
/**
* A taint-tracking configuration that matches sources and sinks in the same
* way as the `tainted` predicate.
*
* Override `isSink` and `taintThroughGlobals` as needed, but do not provide
* a characteristic predicate.
*/
class TaintTrackingConfiguration extends TSingleton {
/** Override this to specify which elements are sources in this configuration. */
predicate isSource(Expr source) { exists(getNodeForSource(source)) }
/** Override this to specify which elements are sinks in this configuration. */
abstract predicate isSink(Element e);
/** Override this to specify which expressions are barriers in this configuration. */
predicate isBarrier(Expr e) { nodeIsBarrier(getNodeForExpr(e)) }
/**
* Override this predicate to `any()` to allow taint to flow through global
* variables.
*/
predicate taintThroughGlobals() { none() }
/** Gets a textual representation of this element. */
string toString() { result = "TaintTrackingConfiguration" }
}
private class AdjustedConfiguration extends TaintTracking3::Configuration {
AdjustedConfiguration() { this = "AdjustedConfiguration" }
override predicate isSource(DataFlow::Node source) {
exists(TaintTrackingConfiguration cfg, Expr e |
cfg.isSource(e) and source = getNodeForExpr(e)
)
}
override predicate isSink(DataFlow::Node sink) {
exists(TaintTrackingConfiguration cfg | cfg.isSink(adjustedSink(sink)))
}
override predicate isAdditionalTaintStep(DataFlow::Node n1, DataFlow::Node n2) {
// Steps into and out of global variables
exists(TaintTrackingConfiguration cfg | cfg.taintThroughGlobals() |
writesVariable(n1.asInstruction(), n2.asVariable().(GlobalOrNamespaceVariable))
or
readsVariable(n2.asInstruction(), n1.asVariable().(GlobalOrNamespaceVariable))
)
or
additionalTaintStep(n1, n2)
}
override predicate isSanitizer(DataFlow::Node node) {
exists(TaintTrackingConfiguration cfg, Expr e | cfg.isBarrier(e) and node = getNodeForExpr(e))
}
override predicate isSanitizerIn(DataFlow::Node node) { nodeIsBarrierIn(node) }
}
/*
* A sink `Element` may map to multiple `DataFlowX::PathNode`s via (the
* inverse of) `adjustedSink`. For example, an `Expr` maps to all its
* conversions, and a `Variable` maps to all loads and stores from it. Because
* the path node is part of the tuple that constitutes the alert, this leads
* to duplicate alerts.
*
* To avoid showing duplicates, we edit the graph to replace the final node
* coming from the data-flow library with a node that matches exactly the
* `Element` sink that's requested.
*
* The same is done for sources.
*/
private newtype TPathNode =
TWrapPathNode(DataFlow3::PathNode n) or
// There's a single newtype constructor for both sources and sinks since
// that makes it easiest to deal with the case where source = sink.
TEndpointPathNode(Element e) {
exists(AdjustedConfiguration cfg, DataFlow3::Node sourceNode, DataFlow3::Node sinkNode |
cfg.hasFlow(sourceNode, sinkNode)
|
sourceNode = getNodeForExpr(e) and
exists(TaintTrackingConfiguration ttCfg | ttCfg.isSource(e))
or
e = adjustedSink(sinkNode) and
exists(TaintTrackingConfiguration ttCfg | ttCfg.isSink(e))
)
}
/** An opaque type used for the nodes of a data-flow path. */
class PathNode extends TPathNode {
/** Gets a textual representation of this element. */
string toString() { none() }
/**
* Holds if this element is at the specified location.
* The location spans column `startcolumn` of line `startline` to
* column `endcolumn` of line `endline` in file `filepath`.
* For more information, see
* [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
*/
predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
none()
}
}
/**
* INTERNAL: Do not use.
*/
module Private {
/** Gets a predecessor `PathNode` of `pathNode`, if any. */
PathNode getAPredecessor(PathNode pathNode) { edges(result, pathNode) }
/** Gets the element that `pathNode` wraps, if any. */
Element getElementFromPathNode(PathNode pathNode) {
exists(DataFlow::Node node | node = pathNode.(WrapPathNode).inner().getNode() |
result = node.asInstruction().getAst()
or
result = node.asOperand().getDef().getAst()
)
or
result = pathNode.(EndpointPathNode).inner()
}
}
private class WrapPathNode extends PathNode, TWrapPathNode {
DataFlow3::PathNode inner() { this = TWrapPathNode(result) }
override string toString() { result = this.inner().toString() }
override predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
this.inner().hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
}
}
private class EndpointPathNode extends PathNode, TEndpointPathNode {
Expr inner() { this = TEndpointPathNode(result) }
override string toString() { result = this.inner().toString() }
override predicate hasLocationInfo(
string filepath, int startline, int startcolumn, int endline, int endcolumn
) {
this.inner()
.getLocation()
.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
}
}
/** A PathNode whose `Element` is a source. It may also be a sink. */
private class InitialPathNode extends EndpointPathNode {
InitialPathNode() { exists(TaintTrackingConfiguration cfg | cfg.isSource(this.inner())) }
}
/** A PathNode whose `Element` is a sink. It may also be a source. */
private class FinalPathNode extends EndpointPathNode {
FinalPathNode() { exists(TaintTrackingConfiguration cfg | cfg.isSink(this.inner())) }
}
/** Holds if `(a,b)` is an edge in the graph of data flow path explanations. */
query predicate edges(PathNode a, PathNode b) {
DataFlow3::PathGraph::edges(a.(WrapPathNode).inner(), b.(WrapPathNode).inner())
or
// To avoid showing trivial-looking steps, we _replace_ the last node instead
// of adding an edge out of it.
exists(WrapPathNode sinkNode |
DataFlow3::PathGraph::edges(a.(WrapPathNode).inner(), sinkNode.inner()) and
b.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
or
// Same for the first node
exists(WrapPathNode sourceNode |
DataFlow3::PathGraph::edges(sourceNode.inner(), b.(WrapPathNode).inner()) and
sourceNode.inner().getNode() = getNodeForExpr(a.(InitialPathNode).inner())
)
or
// Finally, handle the case where the path goes directly from a source to a
// sink, meaning that they both need to be translated.
exists(WrapPathNode sinkNode, WrapPathNode sourceNode |
DataFlow3::PathGraph::edges(sourceNode.inner(), sinkNode.inner()) and
sourceNode.inner().getNode() = getNodeForExpr(a.(InitialPathNode).inner()) and
b.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
}
/**
* Holds if there is flow from `arg` to `out` across a call that can by summarized by the flow
* from `par` to `ret` within it, in the graph of data flow path explanations.
*/
query predicate subpaths(PathNode arg, PathNode par, PathNode ret, PathNode out) {
DataFlow3::PathGraph::subpaths(arg.(WrapPathNode).inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), out.(WrapPathNode).inner())
or
// To avoid showing trivial-looking steps, we _replace_ the last node instead
// of adding an edge out of it.
exists(WrapPathNode sinkNode |
DataFlow3::PathGraph::subpaths(arg.(WrapPathNode).inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), sinkNode.inner()) and
out.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
or
// Same for the first node
exists(WrapPathNode sourceNode |
DataFlow3::PathGraph::subpaths(sourceNode.inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), out.(WrapPathNode).inner()) and
sourceNode.inner().getNode() = getNodeForExpr(arg.(InitialPathNode).inner())
)
or
// Finally, handle the case where the path goes directly from a source to a
// sink, meaning that they both need to be translated.
exists(WrapPathNode sinkNode, WrapPathNode sourceNode |
DataFlow3::PathGraph::subpaths(sourceNode.inner(), par.(WrapPathNode).inner(),
ret.(WrapPathNode).inner(), sinkNode.inner()) and
sourceNode.inner().getNode() = getNodeForExpr(arg.(InitialPathNode).inner()) and
out.(FinalPathNode).inner() = adjustedSink(sinkNode.inner().getNode())
)
}
/** Holds if `n` is a node in the graph of data flow path explanations. */
query predicate nodes(PathNode n, string key, string val) {
key = "semmle.label" and val = n.toString()
}
/**
* Holds if `tainted` may contain taint from `source`, where `sourceNode` and
* `sinkNode` are the corresponding `PathNode`s that can be used in a query
* to provide path explanations. Extend `TaintTrackingConfiguration` to use
* this predicate.
*
* A tainted expression is either directly user input, or is computed from
* user input in a way that users can probably control the exact output of
* the computation.
*/
predicate taintedWithPath(Expr source, Element tainted, PathNode sourceNode, PathNode sinkNode) {
exists(AdjustedConfiguration cfg, DataFlow3::Node flowSource, DataFlow3::Node flowSink |
source = sourceNode.(InitialPathNode).inner() and
flowSource = getNodeForExpr(source) and
cfg.hasFlow(flowSource, flowSink) and
tainted = adjustedSink(flowSink) and
tainted = sinkNode.(FinalPathNode).inner()
)
}
private predicate isGlobalVariablePathNode(WrapPathNode n) {
n.inner().getNode().asVariable() instanceof GlobalOrNamespaceVariable
}
private predicate edgesWithoutGlobals(PathNode a, PathNode b) {
edges(a, b) and
not isGlobalVariablePathNode(a) and
not isGlobalVariablePathNode(b)
}
/**
* Holds if `tainted` can be reached from a taint source without passing
* through a global variable.
*/
predicate taintedWithoutGlobals(Element tainted) {
exists(AdjustedConfiguration cfg, PathNode sourceNode, FinalPathNode sinkNode |
cfg.isSource(sourceNode.(WrapPathNode).inner().getNode()) and
edgesWithoutGlobals+(sourceNode, sinkNode) and
tainted = sinkNode.inner()
)
}
}

29
cpp/ql/lib/semmle/code/cpp/security/TaintTrackingImpl.qll
View File

@@ -121,7 +121,9 @@ private predicate moveToDependingOnSide(Expr src, Expr dest) {
* (this is done to avoid false positives). Because of this we need to track if the tainted element came from an argument
* or not, and for that we use destFromArg
*/
private predicate betweenFunctionsValueMoveTo(Element src, Element dest, boolean destFromArg) {
deprecated private predicate betweenFunctionsValueMoveTo(
Element src, Element dest, boolean destFromArg
) {
not unreachable(src) and
not unreachable(dest) and
(
@@ -162,13 +164,13 @@ private predicate betweenFunctionsValueMoveTo(Element src, Element dest, boolean
// predicate folding for proper join-order
// bad magic: pushes down predicate that ruins join-order
pragma[nomagic]
private predicate resolveCallWithParam(Call call, Function called, int i, Parameter p) {
deprecated private predicate resolveCallWithParam(Call call, Function called, int i, Parameter p) {
called = resolveCall(call) and
p = called.getParameter(i)
}
/** A variable for which flow through is allowed. */
library class FlowVariable extends Variable {
deprecated library class FlowVariable extends Variable {
FlowVariable() {
(
this instanceof LocalScopeVariable or
@@ -179,11 +181,11 @@ library class FlowVariable extends Variable {
}
/** A local scope variable for which flow through is allowed. */
library class FlowLocalScopeVariable extends Variable {
deprecated library class FlowLocalScopeVariable extends Variable {
FlowLocalScopeVariable() { this instanceof LocalScopeVariable }
}
private predicate insideFunctionValueMoveTo(Element src, Element dest) {
deprecated private predicate insideFunctionValueMoveTo(Element src, Element dest) {
not unreachable(src) and
not unreachable(dest) and
(
@@ -324,7 +326,7 @@ private predicate unionAccess(Variable v, Field f, FieldAccess a) {
a.getQualifier() = v.getAnAccess()
}
GlobalOrNamespaceVariable globalVarFromId(string id) {
deprecated GlobalOrNamespaceVariable globalVarFromId(string id) {
if result instanceof NamespaceVariable
then id = result.getNamespace() + "::" + result.getName()
else id = result.getName()
@@ -353,7 +355,7 @@ private predicate hasUpperBoundsCheck(Variable var) {
}
cached
private predicate taintedWithArgsAndGlobalVars(
deprecated private predicate taintedWithArgsAndGlobalVars(
Element src, Element dest, boolean destFromArg, string globalVar
) {
isUserInput(src, _) and
@@ -395,7 +397,7 @@ private predicate taintedWithArgsAndGlobalVars(
* This doesn't include data flow through global variables.
* If you need that you must call taintedIncludingGlobalVars.
*/
predicate tainted(Expr source, Element tainted) {
deprecated predicate tainted(Expr source, Element tainted) {
taintedWithArgsAndGlobalVars(source, tainted, _, "")
}
@@ -410,7 +412,7 @@ predicate tainted(Expr source, Element tainted) {
* The parameter `globalVar` is the name of the last global variable used to move the
* value from source to tainted.
*/
predicate taintedIncludingGlobalVars(Expr source, Element tainted, string globalVar) {
deprecated predicate taintedIncludingGlobalVars(Expr source, Element tainted, string globalVar) {
taintedWithArgsAndGlobalVars(source, tainted, _, globalVar)
}
@@ -541,14 +543,14 @@ private predicate returnArgument(Function f, int sourceArg) {
* targets a virtual method, simple data flow analysis is performed
* in order to identify target(s).
*/
Function resolveCall(Call call) {
deprecated Function resolveCall(Call call) {
result = call.getTarget()
or
result = call.(DataSensitiveCallExpr).resolve()
}
/** A data sensitive call expression. */
abstract library class DataSensitiveCallExpr extends Expr {
abstract deprecated library class DataSensitiveCallExpr extends Expr {
DataSensitiveCallExpr() { not unreachable(this) }
abstract Expr getSrc();
@@ -579,7 +581,7 @@ abstract library class DataSensitiveCallExpr extends Expr {
}
/** Call through a function pointer. */
library class DataSensitiveExprCall extends DataSensitiveCallExpr, ExprCall {
deprecated library class DataSensitiveExprCall extends DataSensitiveCallExpr, ExprCall {
override Expr getSrc() { result = getExpr() }
override Function resolve() {
@@ -588,7 +590,8 @@ library class DataSensitiveExprCall extends DataSensitiveCallExpr, ExprCall {
}
/** Call to a virtual function. */
library class DataSensitiveOverriddenFunctionCall extends DataSensitiveCallExpr, FunctionCall {
deprecated library class DataSensitiveOverriddenFunctionCall extends DataSensitiveCallExpr,
FunctionCall {
DataSensitiveOverriddenFunctionCall() {
exists(getTarget().(VirtualFunction).getAnOverridingFunction())
}